The present invention relates generally to the field of snow skis. More specifically, the present invention discloses snow skis having asymmetrical lateral edges.
A variety of types of skis are currently in use. The present invention is intended primarily for telemark skiing, although it can be readily adapted for other types of skis, including the following types of skis in common use:
The xe2x80x9calpine skixe2x80x9d, or fixed heel ski, is characterized by its utilization rather than its design. The binding by which a skier""s boot is attached to the ski secures both the toe and heel of the ski boot to the ski simultaneously. This method of binding characterizes the use of this ski as xe2x80x9calpine.xe2x80x9d In alpine skiing, both skis are generally maintained parallel to one another. The skier turns by shifting weight to the medial edge of the outside ski (i.e., the ski farther from the center of the circle describing the turn).
The xe2x80x9ctelemark skixe2x80x9d, or free heel ski, is similarly characterized by its utilization rather than its design. The binding by which the skier""s boot is attached to the ski causes only the toe component of the ski boot to be fixed to the ski, while leaving the heel free to rise off the ski. Other than the binding, the ski is essentially the same as an alpine ski. Turning in telemark skiing is quite different than in alpine skiing. The skier positions the inside ski (i.e., the ski closer to the center of the circle describing the turn) behind the outside ski, so that the heel of the inside boot is raised off the inside ski. Any pressure applied by the skier to the inside ski is exerted via the toe area of the boot (i.e., the general area between the ball of the skier""s foot to the lip of the boot). In contrast, the outside boot remains flat against the outside ski, so that pressure is exerted on the ski over the entire area of the ski boot. When the inside boot is raised and the outside boot remains flat, a xe2x80x9ctelemark posturexe2x80x9d is attained.
In telemark skiing, the points of applied pressure (resulting from the skier""s application of weight and resulting additional forces) exist at different locations along the longitudinal axes of each ski. The inside ski (i.e., the ski closer to the center of the circle describing the turn) receives the application of pressure at the toe area of the attached boot. The outside ski receives the application of pressure along the entire bottom of the boot""s sole.
The xe2x80x9cactive edgexe2x80x9d refers to the edge of each ski closer to the center of the turn being executed, i.e., the inside edge of the turn. By tilting the ski and applying pressure on the active edge, the active edge of each ski engages the underlying snow surface causing the ski to turn.
The xe2x80x9ccross-country skixe2x80x9d is similar to the telemark ski, except that it is designed for flatter terrain. Cross-country skis tend to be narrower and lighter than telemark skis.
The xe2x80x9crandonxc3xa9e skixe2x80x9d is a hybrid of free heel and fixed heel skis, wherein the heel binding can either be fixed or free at the option of the skier.
The prior art in the field includes the following:
xe2x80x9cOpen the Toy Box,xe2x80x9d Skiing Trade News, page 20 (January, 1997)
xe2x80x9cAll Aboard! Ski and Snowboard Design Rides the Boom into the Backcountry,xe2x80x9d Seattle Post-Intelligencer, Getaways, page 8 (Oct. 23, 1997)
xe2x80x9cArc Angles: We Test Some Skis You Can Bank On,xe2x80x9d Skiing, page 108 (vol. 49, no. 4, December 1997)
xe2x80x9cInbounds Adventure,xe2x80x9d Skiing, page 124 (vol. 51, no.1, September 1998)
xe2x80x9cA Slice of Heaven,xe2x80x9d Skiing, page 156 (vol. 51, no. 3, November 1998)
The article from Skiing Trade News mentions and shows a picture of the xe2x80x9cRadarcxe2x80x9d skis introduced by Fischer GmBH of Austria. The articles from the Seattle Post-Intelligencer and Skiing also describe the Fischer Radarc skis. The Fischer Radarc skis have asymmetrical side cuts with the longer edges on the outside of the skis, which is opposite from the present invention. The side cut on the outer edge is shifted farther bask toward the tail of the ski than the side cut on the inside edge. This arrangement is also backward from the present invention. It appears that the Radarc ski is intended for a specialized style of alpine skiing known as xe2x80x9ccarvingxe2x80x9d, in which the skier""s legs are spread apart and turns are made by exerting substantially equal force on the active edges of both skis. The active edges make substantially concentric circles for both skis. Therefore, since the outside ski turns with a larger radius than the inside ski when carving, it may be advantageous for the medial edge of the outside ski to have a larger radius than the lateral edge of the inside ski. However, it should be expressly understood that the Radarc ski addresses a completely different problem and teaches away from the present invention.
Meatto et al. disclose asymmetrical alpine skis with offset boot platforms. The medial edges of the skis have side cuts but the outer edges are substantially straight.
Fagot discloses an alpine ski with a symmetrical bottom surface, but having asymmetrical, inwardly sloping sidewalls.
Gauer discloses a short symmetrical alpine ski that is convex from front to rear, and also convex from side to side.
Floreani, Nelson, Karlsen, Petkov, and Richmond disclose other examples of symmetrical skis of various types.
Staufer discloses a symmetrical alpine ski with a series of side cuts along both edges.
In addition to the prior art discussed above, several types of asymmetrical snowboards have been marketed in the past. Snowboard bindings typically hold the rider""s feet at a diagonal angle with respect the snowboard. As a result, the center of pressure shifts Slightly forward or rearward as the rider transfers his weight to the right or left edges to turn the snowboard. Some snowboards compensate for this axial shift in the center of pressure by placing the point of maximum side cut on the right side of the board further forward than on the left side, for a right-footed snowboarder. This would be reversed for a left-footed snowboarder.
Properly designed skis must accommodate a number of concerns in today""s highly competitive market. It is particularly important that the skier should be able to execute turns without undue effort, and that the skis should be stable and easy to control. The prior art listed above has several shortcomings, particularly with regard to telemark skiing:
(a) Asymmetrical Edge Pressure Problem With Existing Snow Skis
In the telemark posture, it is difficult to apply a large amount of pressure on the active edge of the inside ski, because the knee over that ski is bent and contact with that ski is only made by the toe area of the boot. Since there is less pressure on the active edge of the inside ski, it is more difficult to turn that ski. However, in the telemark posture, it is comfortable and easy to apply pressure on the active edge of the outside ski, because the knee over that ski is straighter and the contact with the ski is made by the entire bottom of the boot. Since there is more pressure on the active edge of the outside ski, it is easier to turn that ski.
In the utilization of existing telemark ski equipment in the telemark posture, the amount of pressure on the active edge of the inside ski is significantly less than the amount of pressure on the active edge of the outside ski, owing to the different locations of application of pressure for each of the two skis when a telemark posture is employed. In order to best turn both skis together, it would be ideal if the pressure on each active edge were close to equal. The problem with existing skis is that their design results in a substantial disparity of pressure on the active edges.
(b) The Center of Pressure Problem With Existing Snow Skis
As previously discussed, turns are accomplished on skis by applying pressure on the active edge. The active edge turns the ski by virtue of its shape, which is curved inward toward the center of the ski, as shown for example in FIGS. 4 and 5. Since this curvature is achieved by effectively cutting out the side of the ski, it is known in the ski industry as xe2x80x9cside cutxe2x80x9d. The point along the edge having the greatest side cut can be referred to as xe2x80x9cmaximum side cut.xe2x80x9d Maximum side cut can also be defined as the point along the edge that is furthest from an imaginary straight line running between the two ends of the edge.
The center of pressure on a ski is the point underneath the boot denoting the center of downward pressure from the skier onto the ski. On any snow ski, there is a particular point either at maximum side cut, or very close to it, where it is best to have the center of pressure located for optimal turning. Ski manufacturers typically mark that point xe2x80x9cboot centerxe2x80x9d, and bindings are mounted on the ski so that the center of pressure is at that point.
Existing snow skis are constructed so that maximum side cut on each edge is located at the same point along the length of the ski on each side. This symmetrical arrangement of maximum side cuts makes sense for alpine skiing, where the boot is fixed in one place. In telemark skiing, due to the telemark posture, there are two different centers of pressure on each ski. One center of pressure is under the middle of the boot sole when the ski is the outside ski and the boot is resting flat on the ski. However, when the ski is the inside ski, the skier""s knee is bent so that the heel rises, and the center of pressure shifts forward and is located under the toe area of the boot. Symmetrical maximum side cuts on existing skis are not well-suited for telemark skiing because they are designed as if there were only one center of pressure, This flaw results in the telemark, skier""s application of pressure in a location on the inside ski that is not ideal for the physical properties of the curved edge.
(c) Proportional Length Problem With Existing Telemark Skis
Skis are typically designed with predetermined proportions of the ski in front and behind the center of pressure exerted by the skier""s boot. For example, many conventional skis are optimal if have approximately 55% of their length is in front of, and approximately 45% is behind the center of pressure. In telemark skiing, the center of pressure for the inside ski shifts forward when turning, as previously discussed. This also shifts the proportion of the ski in front and behind the center of pressure, resulting in less than optimal performance for that ski, and causing a disparity with the proportional lengths of the other ski.
The present invention addresses the edge pressure problem discussed above by shortening the active edge of the inside ski. By reducing the length of the active edge receiving less pressure, the lineal force along that active edge is increased so it is brought closer to parity with the lineal force on the active edge of the outside ski. This leads to increased facility and fluidity while turning. In other words, the present invention makes it easier to turn the inside ski by shortening the active edge of that ski.
The present invention also solves the problem of having two centers of pressure in telemark skiing by locating the point of maximum side cut at a point along each edge corresponding to the location of the center of pressure when that edge is the active edge. By locating the point of maximum side cut for each active edge according to that edge""s center of pressure, the present invention increases the maneuverability and responsiveness of the skis.
The present invention also solves the proportional length problem associated with conventional telemark skis by using different medial and outer edge lengths.
This invention provides snow skis having asymmetrical edges to make turning easier. In particular, each ski has concave, curved lateral edges, whereby the medial edge of each ski is substantially longer than its outer edge. In addition, the points of maximum side cut on the ski edges can be asymmetrical with one in front of the other. The point of maximum side cut on the outer edge is generally adjacent to the toe area of skier""s boot, while the point of maximum side cut on the medial edge is generally adjacent to the middle of the ski boot to facilitate easier turns while telemark skiing. These and other advantages, features, and objects of the present invention will be more readily understood in view of the following detailed description and the drawings.